Two drugmakers said Friday their COVID-19 vaccine candidate won't be ready until late 2021.
GlaxoSmithKline and Sanofi said interim results from a combined phase one/phase two clinical trial showed an "insufficient response" in older adults.
The finding "demonstrates the need to refine the concentration of antigen in order to provide high-level immune response across all age groups," they said in a statement.
The companies are planning a Phase 2b study with an improved antigen, with support from President Donald Trump's administration, to start in February 2021. The improved antigen showed good results in a study in non-human primates.
The vaccine isn't expected to be ready until quarter four of next year, pending successful completion of the new plan.
“We care greatly about public health which is why we are disappointed by the delay announced today, but all our decisions are and will always be driven by science and data. We have identified the path forward and remain confident and committed to bringing a safe and efficacious COVID-19 vaccine. Following these results and the latest encouraging new preclinical data, we will now work to further optimise our candidate to achieve this goal,” said Thomas Triomphe, executive vice president and head of Sanofi, in a statement.
"The results of the study are not as we hoped. Based on previous experience and other collaborations, we are confident that GSK’s pandemic adjuvant system, when coupled with a COVID-19 antigen, can elicit a robust immune response with an acceptable reactogenicity profile," added Roger Connor, president of GlaxoSmithKline, or GSK.
A third vaccine poised to receive early approval is being studied further after questions were raised about the vaccine’s preliminary results.